NullReferenceException: Object reference not set to an instance of an object
时间: 2023-11-05 18:34:47 浏览: 37
This error occurs when you try to access an object or variable that has not been initialized or assigned a value. In other words, you are trying to use something that does not exist or is null.
To fix the issue, you need to check whether the object or variable is null before using it. You can use an if statement or the null-coalescing operator (??) to check for null values and provide a default value or handle the exception accordingly.
For example, instead of writing:
string myString = null;
Console.WriteLine(myString.Length);
You can write:
string myString = null;
if (myString != null)
{
Console.WriteLine(myString.Length);
}
else
{
Console.WriteLine("myString is null");
}
Or you can use the null-coalescing operator to provide a default value:
string myString = null;
Console.WriteLine(myString?.Length ?? 0);
This will output 0 if myString is null.
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